Propellant for spacecraft and / or missiles and / or satellites

Abstract

The invention relates to a propellant and to use of such a propellant for spacecraft and / or missiles and / or satellites, the propellant comprising a fuel and exactly one additive. The exactly one additive is an energetic inhibitor that acts as a phlegmatizing agent and reduces the ignition temperature of the propellant.

Description

[0001] Description

[0002] FUEL FOR SPACECRAFT AND / OR AIRCRAFT

[0003] AND / OR SATELLITES

[0004] State of the art

[0005] The invention relates to a fuel for spacecraft and / or missiles and / or satellites.

[0006] Liquid monergol propellants are often used for the orbit and attitude control of satellites and missiles. Since only one tank and one set of components for propellant delivery are required, very simple and inexpensive systems can be implemented in this way.

[0007] Hydrazine is currently the standard fuel used in such systems. The decomposition of this substance, necessary for ignition and operation of such an engine, can be easily achieved using indium-platinum-based catalysts. The decomposition gases, i.e., the reactive propellant produced during decomposition, have a relatively low temperature of approximately 800 K, allowing for simple design without the use of expensive high-temperature materials. Despite this, a relatively high thrust can be achieved: the theoretical specific impulse is 1979 m / s. However, the disadvantages of using hydrazine include the high costs associated with handling this substance. This is due to its high toxicity and carcinogenicity. To address this challenge, a number of alternative fuels have been researched, developed, and tested.One approach to realizing such so-called "green propellants" involves preparing solutions of solid explosive oxidizers like hydroxyl ammonium nitrate (HAN) and ammonium dinitramide (ADN) in water and then adding a fuel component, such as methanol or ammonia, to create a premixed reactive mixture or explosive substance that is nevertheless insensitive enough to be used as a propellant. Such propellants typically have a higher volumetric and mass-specific impulse than hydrazine.

[0008] However, HAN- and ADN-based propellants have high production costs. In addition, these propellants also have significantly higher combustion temperatures than hydrazine, which has so far posed a challenge for the construction materials of such engines. Furthermore, propellants based on solutions of energetic materials in water are difficult to ignite, as the water must first be evaporated from the solution for successful combustion.

[0009] Another approach is the use of natural, i.e., unmixed, monergols. In this context, the use of highly concentrated hydrogen peroxide solutions (90 wt.% to 98 wt.% in water; wt.% = weight percent) is particularly noteworthy. This relatively non-toxic substance, like hydrazine, can be catalytically decomposed quite easily. The major drawbacks of hydrogen peroxide solutions are their low performance compared to other similar propellants, as well as their low stability, which limits their long-term storage. The use of nitromethane also represents a potential "green propellant." This substance is an inexpensive and widely available laboratory solvent, but it possesses properties that significantly complicate its use as an aerospace propellant. It exhibits no or only unstable combustion at low combustion chamber pressures and has poor ignitability.The material is very sensitive to impact and is considered explosive.

[0010] EP 2 662 350 B1 discloses a gel-like, monergolic fuel in which the high combustion temperature is reduced by adding an additive to the fuel which, during combustion of the fuel, oxidizes the carbon to carbon monoxide and does not provide oxygen for the oxidation of hydrogen to water and of carbon monoxide to carbon dioxide.

[0011] EP 2 607 337 B1 discloses a gel-shaped, injectable single-component fuel consisting of a mixture of at least one monergolic base fuel, namely a hydrocarbon containing at least one nitro group, and at least one gelling agent consisting of carbon particles or carbon nanotubes and at least one solid oxidizer with an average particle size of at most 0.4 millimeters.

[0012] Disclosure of the invention

[0013] The object of the invention is to create a propellant with improved properties for spacecraft and / or missiles and / or satellites.

[0014] The problems are solved by the features of the independent claim. Favorable embodiments and advantages of the invention arise from the further claims, the description, and the drawings. The features listed individually in the patent claims can be combined in a technologically meaningful way and can be supplemented by explanatory facts from the description and by details from the figures, thereby demonstrating further embodiments of the invention.

[0015] According to one aspect of the invention, a propellant for spacecraft and / or missiles and / or satellites is proposed, wherein the propellant comprises a fuel and exactly one additive, the exact one additive being an energy inhibitor that simultaneously acts as a phlegmatizing agent and lowers the ignition temperature of the propellant. This enables reliable ignition of the propellant. The propellant can be used in pulsed operation of spacecraft engines. Furthermore, the preheating temperature of a spacecraft ignition device can be reduced, which can improve the overall performance of the spacecraft. Handling and transport of the propellant can also be facilitated due to its reduced shock sensitivity.

[0016] The fuel can be a solvent or comprise one or more solvents. The solvent can be, for example, a monohydric or dihydric alcohol. The fuel can be an organic nitro compound. The fuel exhibits performance characteristics related to flammability and combustion behavior. Furthermore, other properties, such as behavior during transport, particularly shock sensitivity, and storage, such as segregation, can be important for the fuel's use in spacecraft. The addition of precisely one additive, acting as an energy inhibitor, to the fuel can simultaneously reduce its sensitivity to mechanical stimuli and improve its ignitability, thus positively influencing the overall combustion process of the fuel.This additive can transfer its properties, particularly its insensitivity to mechanical stimuli, to the fuel. Furthermore, the additive can also transfer its ability to decompose exothermically upon reaching a critical temperature to the fuel, thus simultaneously acting as a phlegmatizing agent and an agent that improves ignition behavior. The addition of this single additive lowers the temperature at which exothermic decomposition can occur. According to established teaching in the prior art, the addition of a phlegmatizing agent improves shock resistance but deteriorates combustion behavior. For use as a fuel, the prior art discloses and requires the addition of a second substance.Consequently, the prior art teaching involves adding at least two additives to the fuel to achieve the desired result, namely improved impact resistance combined with improved ignition behavior. Surprisingly, experiments conducted within the scope of the invention revealed that precisely one additive and its proportion in the fuel mixture can simultaneously act as a phlegmatizing agent and lower the ignition temperature.

[0017] Since only one additive is mixed with the fuel, this can advantageously lead to improved mixing behavior between the fuel and the additive. Furthermore, the addition of precisely this one additive, which acts as an energy inhibitor, can significantly simplify the manufacturing process and quality control.

[0018] The energetic inhibitor prevents the heat and intermediate products generated during the decomposition process of the additive, thus significantly improving the overall combustion behavior of the propellant. This can be achieved through complete combustion of the propellant and / or the additive, leaving no residue after combustion. If several additives are mixed into the propellant, as is the case with prior art propellants, partial segregation can occur because different additives may exhibit different mixing properties. This can lead to the precipitation of solid components, which in turn can cause incomplete combustion of the propellant. After exiting a spacecraft or missile nozzle, the unburned components can recrystallize, forming dust and slag.These unburned residues, dust and slag could, for example, settle on solar modules and / or optical equipment of the spacecraft or missile and damage them or impair their function.

[0019] According to a favorable embodiment of the invention, it is proposed that the additive contains or is formed from exactly one additive, 5-methyl-1-hydroxyltetrazol (5MTE).

[0020] 5-Methyl-1-hydroxyltetrazole (5MTE) is a heterocyclic compound belonging to the group of organic tetrazoles. 5-Methyl-1-hydroxyltetrazole (5MTE) contains an alkyl group. 5-Methyl-1-hydroxyltetrazole (5MTE) can exhibit explosive behavior. Therefore, 5MTE can improve the performance characteristics of the fuel, for example, by lowering the ignition temperature and positively influencing combustion behavior. Surprisingly, despite the known explosive properties of 5MTE, a phlegmatizing effect was observed in tests using the so-called BAM impact hammer method. Another advantage is that 5MTE is liquid at room temperature and thus mixes well with the fuel. The amount of 5-Methyl-1-hydroxyltetrazole in the fuel can conveniently range from 10% to 40% by weight.

[0021] The phlegmatizing effect of 5MTE can occur because, in one of the first and most important steps of the thermal decomposition of nitromethane, it is based on collisions between nitromethane molecules and their fragments. If another substance, such as 5MTE, is present in the gas phase, the number of nitromethane molecules that can collide with each other may be smaller. This might also apply to reactions in the liquid phase, if such reactions occur.

[0022] According to a further advantageous embodiment of the invention, it is proposed that the additive contains exactly one additive, dimethyl sulfoxide (DMSO), or is formed from it.

[0023] Dimethyl sulfoxide (DMSO) can act as an oxidizing agent. Because DMSO can function as an oxidizing agent, it can improve the performance characteristics of the fuel, particularly by lowering the ignition temperature and thus improving the overall combustion behavior. Tests have shown that adding DMSO to the fuel can also improve its shock resistance. Another advantage is that DMSO is liquid at room temperature and therefore mixes well with the fuel. The amount of dimethyl sulfoxide in the fuel can ideally range from 8% to 35% by weight.

[0024] The phlegmatizing effect of DMSO can occur because, in one of the first and most important steps of the thermal decomposition of nitromethane, it is based on collisions between nitromethane molecules and their fragments. If another substance, such as DMSO, is present in the gas phase, the number of nitromethane molecules that can collide with each other may be smaller. This might also apply to reactions in the liquid phase, if such reactions occur.

[0025] According to a further embodiment of the invention, it is proposed that the additive contains exactly one additive, ethyl ammonium nitrate (EAN), or is formed from it.

[0026] Ethyl ammonium nitrate (EAN), due to its nitrate anion, can have an oxidizing effect and thus improve the fuel's performance characteristics, in particular by lowering the ignition temperature and positively influencing, especially accelerating, the combustion behavior. Tests have also demonstrated that the fuel's shock sensitivity can be reduced by adding EAN. Furthermore, EAN is liquid at room temperature and therefore mixes well with the fuel. The amount of ethyl ammonium nitrate in the fuel can ideally range from 5% to 20% by weight.

[0027] The phlegmatizing effect of EAN can occur, for example, because one of the first and most important steps in the thermal decomposition of nitromethane is based on collisions between nitromethane molecules and their fragments. If another substance, such as EAN, is present in the gas phase, the number of nitromethane molecules that can collide with each other may be smaller. This might also apply to reactions in the liquid phase, if such reactions occur.

[0028] EAN is currently known as a fuel. Further investigations have focused on improving the performance of EAN fuel by adding nitromethane. These investigations specifically concerned the addition of nitromethane to EAN, as the prevailing opinion was that this was the only way to achieve miscibility. The prevailing opinion was that nitromethane as a starting material had miscibility gaps and that at least one third substance was necessary to achieve miscibility and a stable mixture. Surprisingly, the investigations related to the invention revealed that, by selecting the correct ratio of EAN to nitromethane, the two substances can be miscible and do not separate during storage.

[0029] Thus, the single additive, which is an energy inhibitor, can act as a phlegmatizing agent and simultaneously lower the ignition temperature. This can positively influence, and in particular improve, the combustion behavior of the actual fuel. The single additive can exhibit the ability to decompose exothermically once a critical temperature is reached. Exothermic decomposition is characterized by the fact that the heat, as well as the products and / or intermediates formed during the decomposition process, accelerate decomposition and thus the rate of combustion.

[0030] Since the single additive is in liquid form at room temperature, it can be added to the fuel in liquid form. This eliminates the need for water as an additive, as is the case in prior art when using salts as inhibitors that must first be dissolved in water. This avoids the need to expend energy to evaporate the water before the fuel could potentially ignite.

[0031] Depending on the fuel formulation, exactly one additive can contain at least one alkyl group. The alkyl group refers to functional groups within molecules or radicals consisting of aliphatic hydrocarbon chains. The alkyl group can be a Ci-Ce alkyl group or be formed from one. The alkyl group can be bonded to a chemical compound with one or two Ri and / or R2 groups, thus exhibiting the formula: Ri = Ci-C6 alkyl group, Ri = H, Ci-Ce alkyl group, or Ri, R2 = H, Ci-Ce alkyl group.

[0032] Ignitability is the property of flammable substances to ignite without an open flame under defined test conditions. It depends on many parameters: the chemical composition and properties of the substance; state variables such as temperature, pressure, state of matter, surface structure, and moisture content; substance-specific properties such as ignition temperature, explosion limit, heat of combustion, burn rate, and the rate of pyrolysis; oxygen concentration and supply; the temperature, intensity, and duration of exposure to the ignition source; and the presence of catalysts or inhibitors (anticatalysts). Ignitability refers to the behavior of a substance when exposed to a high temperature without a flame. Temperature is only one of many parameters. The characteristic "improvement of ignitability" describes the overall behavior of the fuel, including the combustion itself.The ignition temperature is the temperature to which a substance, contact surface, or mixture must be heated for a flammable substance (solid, liquid, its vapors, or gas) to ignite spontaneously in the presence of oxygen solely due to its temperature—that is, without an ignition source such as a spark. It varies for each substance and, in many cases, depends on the pressure. Spontaneous ignition is caused by an exothermic oxidation reaction when the rate of heat production exceeds the rate of heat loss through conduction, radiation, and convection. The ignition temperature does not correlate with the boiling point or flash point of a flammable substance. Rather, it is a measure of the substance's susceptibility to oxidation.

[0033] The following compounds can advantageously achieve a phlegmatizing effect as well as a reduction in the ignition temperature when added to nitromethane:

[0034] Depending on the fuel formulation, the single additive can comprise a mixture of substances containing an alkyl group. This allows the advantages of one, two, or more substances with an alkyl group to be combined, resulting in improved impact sensitivity and simultaneously improved combustion characteristics.

[0035] Depending on the formulation, the fuel may contain or be composed of nitromethane or a mixture of nitromethane and nitroethane. Nitromethane can be used in an alcoholic solvent. It is a colorless, faintly odorous, highly flammable liquid with a melting point of -29°C and a boiling point of 100.8°C. Nitromethane belongs to the group of monerogolic fuels. The fuel may also contain n-butanol as a solvent.

[0036] In one design of the fuel, the fuel is a gel-like fuel. This gel-like fuel can be produced from a liquid fuel by adding gelling agents. Advantageously, the gel-like fuel can be solid at rest and become fluid under shear stress, such as that generated in suitable injectors. Thus, the fuel can be a gel-like fuel. At rest, the fuel can therefore exist as a nearly solid fuel in a tank and transition to a liquid state, for example, through heating upon entering the combustion chamber. This makes the gel-like fuel advantageously suitable for use in liquid-propellant engines. Liquid-propellant engines can have a compact combustion chamber. Furthermore, the storage of the gel-like fuel is relatively simple. Additionally, a solid substance can be added as an additive to, for example, improve its properties.The gel-like fuel is therefore easy to handle.

[0037] In one embodiment of the fuel, a gelling agent, in particular a gelling agent, is additionally provided. By means of the gelling agent, the liquid fuel, which forms a monergic base fuel, can exhibit a shear-thinning behavior. Thus, the otherwise liquid nitromethane can acquire a viscous behavior and is therefore advantageously easier to handle than liquid nitromethane. Advantageously, the gelling agent can comprise carbon particles, for example, carbon nanotubes.

[0038] Depending on the fuel formulation, the proportion of the gelling agent, in particular the gelling agent, is between 1 wt.% and 10 wt.%. This proportion allows for optimal shear-thinning behavior.

[0039] The addition of 1 wt.% to 10 wt.% organic gelling agent, in particular a low molecular weight organic gelling agent (LMOG), has also proven to be particularly beneficial for improving the impact sensitivity of nitromethane fuel. Such a gelling agent can be, for example, in the form of N-alkylgluconamides, 12-hydroxystearic acid and its salts, (oligo)ureas, alkoxybenzoic acids, N-(oligo-hydroxyalkyl)alkoxybenzamides,

[0040] Alkoxybenzhydrazines and alkoxybenzhydrazides

[0041] Alkoxybenzoylsemicarbazide and alkoxybenzoesulfonic acids are present.

[0042] According to one proposed design of the fuel, the gelling agent is an organic gelling agent and consists of at least one of the following: pyrogenic silica, a low molecular weight organic gelling agent, carbon particles, or carbon nanotubes. These gelling agents are easy and inexpensive to obtain and mix well with the liquid fuel.

[0043] According to another aspect of the invention, the use of a propellant for missiles and / or satellites and / or upper stages of rocket engines is proposed. Thus, the proposed propellant can be universally applicable. In particular, the use of a propellant with the additive 5MTE is proposed. The following sequence must be observed in the production of the propellant. The starting material is the fuel, in particular nitromethane. Process step 1: the nitromethane is provided; the fuel can be in liquid or gel form.

[0044] Process step 2: exactly one additive, which is an energy inhibitor, in particular a phlegmatizing agent, is added to the fuel, in particular the nitromethane.

[0045] In this process, the energetic inhibitor acts as a phlegmatizing agent and as a catalyst when added to the mixture.

[0046] The gelling agent is added to the fuel before the phlegmatizing agent is added. The gelling agent's function is to convert a liquid fuel into a gel-like, and therefore more viscous, state. This is advantageous, for example, because a liquid fuel would immediately leak out of the tank through even a small leak, whereas a gel-like fuel remains in the tank and cannot escape through the small leak. The gelling agent has little or no effect on the fuel's energetic properties. For example, if silica is added as a gelling agent, the fuel's shock resistance is increased. This can be explained by the fact that the nanoparticles significantly increase the reactivity of the nitromethane. The inhibitor is then added to the gel-like fuel.

[0047] drawing

[0048] Further advantages become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations. The drawings show, by way of example:

[0049] Fig. 1 Results of measurements for dynamic differential scanning calorimetry (DSC) in a closed crucible on various propellants for spacecraft and / or missiles according to an embodiment of the invention,

[0050] Fig. 2 Results of DSC measurements in a closed crucible on various propellants for spacecraft and / or missiles according to a further embodiment of the invention.

[0051] Embodiments of the invention

[0052] The figures merely show examples and are not to be understood as limiting.

[0053] Before the invention is described in detail, it should be noted that it is not limited to the respective components of the device or the respective process steps, as these components and processes can vary. The terms used here are intended solely to describe particular embodiments and are not used restrictively. Furthermore, where the singular or indefinite articles are used in the description or in the claims, this also refers to the plural of these elements, unless the overall context clearly indicates otherwise.

[0054] The directional terminology used below, including terms like "left," "right," "above," "below," "in front," "behind," "after," and the like, serves only to improve the understanding of the figure and is in no way intended to limit its generality. The components and elements depicted, their interpretation, and their use may vary according to the considerations of a person skilled in the art and be adapted to the respective applications.

[0055] The proposed propellant, particularly for spacecraft and / or missiles and / or satellites, comprises a fuel and exactly one additive that acts as an energy inhibitor. The energy inhibitor has a phlegmatizing effect, reducing sensitivity to mechanical stimuli, including shocks and impacts. Simultaneously, the additive improves the propellant's ignitability and combustion properties, especially at low combustion chamber pressures. The fuel includes a solvent containing nitromethane or a mixture of nitromethane and nitroethane. The exact one additive is an energy inhibitor. This additive contains at least one alkyl group. An alkyl group is defined as a functional group within molecules or radicals composed of aliphatic hydrocarbon chains.The simplest alkyl group is the methyl group CH3. This is present in 5-methyl-1-hydroxyltetrazol (5MTE) and in dimethyl sulfoxide (DMSO). A more complex alkyl group is the ethyl group, which is present in ethyl ammonium nitrate (EAN). Other more complex alkyl groups include the propyl group and / or the hexyl group. The additive contains or is composed of 5-methyl-1-hydroxyltetrazol (5MTE) and / or dimethyl sulfoxide (DMSO) and / or ethyl ammonium nitrate (EAN).

[0056] Ideally, the proportion of exactly one additive can be 8 wt.% to 35 wt.% DMSO and / or 10 wt.% to 40 wt.% 5MTE and / or 1 wt.% to 20 wt.% EAN.

[0057] The total proportion of additives can advantageously be between 5% and 50% by weight. It is beneficial that the additive can act as an energy inhibitor, i.e., simultaneously as a phlegmatizing agent and lower the ignition temperature, since the addition of multiple additives can be avoided.

[0058] The fuel is a gel-like fuel and contains at least one organic gelling agent, in particular in a proportion of 1 wt.% to 10 wt.%. The organic gelling agent can, for example, be at least one of pyrogenic silica, a low molecular weight organic gelling agent, carbon particles, or carbon nanotubes.

[0059] Table 1 shows examples of different additives in column 1, their respective weight percentages in column 2, and the measured drop hammer impact sensitivity in column 3. The fuel is nitromethane to which the respective additive is added.

[0060] Table 1: Results of drop hammer impact sensitivities for nitromethane fuels, each with exactly one additive acting as an energy inhibitor and containing an alkyl group.

[0061] The impact sensitivity of pure nitromethane is approximately 1 J. The values ​​in Table 1 show that the addition of 5MTE and / or DMSO increases the impact sensitivity. With an addition of 24 wt% 5MTE or 13 wt% DMSO, the impact sensitivity exceeds 50 J. The threshold below which a substance is classified as explosive is 40 J.

[0062] A higher shock sensitivity value means that more energy is required to cause the propellant to explode. Therefore, higher shock sensitivity means that the propellant is more resistant to, for example, sudden shocks.

[0063] The following compounds with the alkyl group are among the substances that simultaneously act as energetic inhibitors, i.e., as phlegmatizing agents, and can improve the ignitability of the fuel by reducing the ignition temperature: Ri=Ci-Ce- alkyl group, Ri=H,Ci-C6-alkyl group, Ri, R2 =H,Ci-C6-alkyl group.

[0064] Table 2 shows the compounds with alkyl residues which, when added to nitromethane, have a phlegmatizing effect and can lower the ignition temperature.

[0065] Table 2: Compounds with alkyl groups: Figure 1 and Figure 2 each show results of measurements as signal curves 10 for dynamic differential scanning calorimetry (DSC) in a closed crucible on various nitromethane propellants for spacecraft and / or missiles according to embodiments of the invention.

[0066] The DSC signals 20 of the DSC measurement, plotted on the y-axis, are shown in units of pV / mg as a function of temperature 30 in °C. Curve 12 represents measurements for pure nitromethane. Curve 14 represents measurements for a nitromethane fuel with 13 wt.% DMSO. Figure 1, which shows the DSC measurement curves of the nitromethane-based fuel, demonstrates that the addition of DMSO (here 13 wt.%) to nitromethane has a catalytic effect at elevated pressures and temperatures. Compared to pure nitromethane, the decomposition, recognizable by the rise and peak of the exothermic reaction, occurs at lower temperatures. Thus, measurement curve 14 shows that the ignition temperature of the nitromethane with the additive DMSO is shifted to lower temperatures. The fuel ignites earlier.

[0067] The ignition temperature, also known as the ignition point, auto-ignition temperature, or ignition point, is the temperature to which a substance, mixture, or contact surface must be heated for a flammable substance, such as fuel, to ignite spontaneously in the presence of oxygen solely due to its temperature—that is, without an ignition source like a spark. It varies for each substance and, in many cases, depends on the pressure. Auto-ignition is caused by an exothermic oxidation reaction when the rate of heat production exceeds the rate of heat loss through conduction, radiation, and convection. The ignition temperature does not correlate with the boiling point or flash point of a flammable substance. Rather, it is a measure of the substance's susceptibility to oxidation.

[0068] Figure 2 shows signal curves 20 from measurements 40 for nitromethane with added 5MTE. Curves 42 and 44 show the DSC signal 20 for pure nitromethane (curve 42) and pure 5MTE (curve 44). Curves 46 show the DSC signal 20 for nitromethane with 16 wt.% 5MTE (curve 46) and nitromethane with 24 wt.% 5MTE (curve 48). It can be seen that the temperature 30 shifts towards a lower temperature 30 with the addition of 5MTE. Furthermore, it is evident that a two-stage combustion behavior occurs with the addition of 16 wt.% 5MTE, i.e., there are two maxima in curve 48.

[0069] Overall, curves 46 and 48 show that the addition of 5MTE to nitromethane has a catalytic effect. Compared to pure nitromethane, the decomposition, recognizable by the rise and peak of the exothermic reaction, occurs at lower temperatures.

[0070] This behavior is particularly pronounced when 24 wt% 5MTE is added to pure nitromethane. The exothermic reaction then occurs at a significantly lower temperature, almost identical to that of pure 5MTE. The pure nitromethane fuel (curves 12, 42) shows the peak of the exothermic reaction at approximately 380°C. Nitromethane fuel with 13 wt% DMSO (curve 14) exhibits a broad peak at approximately 360°C.

[0071] This is consistent with combustion chamber tests as well as so-called beach burner tests. In beach burner tests, a mixture of 85 wt.% nitromethane and 13 wt.% DMSO could still be ignited at 12.5 bar inert gas pressure. In combustion chamber tests, stable combustion was achieved with this mixture at pressures of 13 to 15 bar.

[0072] Based on the presented measurement results, the following nitromethane fuels with additives containing an alkyl group prove to be suitable for various applications:

[0073] Cheap fuels for spacecraft and missiles:

[0074] Nitromethane, 10 wt.% to 40 wt.% 5MTE

[0075] Nitromethane, 8 wt.% to 35 wt.% EAN

[0076] Nitromethane, 5 wt.% to 20 wt.% DMSO. Inexpensive liquid propellants for missiles:

[0077] Nitromethane, 10 wt.% to 40 wt.% 5MTE, 1 wt.% to 10 wt.% Gelling agent

[0078] Nitromethane, 8 wt.% to 35 wt.% EAN, 1 wt.% to 10 wt.% Gelling agent

[0079] Nitromethane, 5 wt.% to 20 wt.% DMSO, 1 wt.% to 10 wt.% Gelling agent

[0080] The propellants can be used for missiles. The propellants described above can also be used for satellites, probes, upper stages, and other rocket engines.

[0081] The following process steps are used in the production of the fuel:

[0082] - Process step 1: a fuel is provided, which can be a liquid fuel or a gel-like fuel.

[0083] - Process step 2: an energy inhibitor is added to the fuel, whereby the energy inhibitor is both a phlegmatizing agent and lowers the ignition temperature.

[0084] Different gelling agents can be added to the fuel before it is spread, in order to form the gel-like fuel from the liquid fuel, for example nitromethane.

[0085] It is important to adhere to the sequence, as the manufacturing process would otherwise be unreliable. For example, before the first process step, it must be decided whether a liquid or a gel-like fuel is required. The gelling agent must then be added accordingly before process step 1. Similarly, the inhibitor must always be added to the fuel before any catalyst is added, as the process would otherwise be unreliable. In the process according to the invention, an energetic inhibitor is used that has both an effect of improving impact resistance and lowering the ignition temperature.

[0086] Reference sign

[0087] 10 measurement curves

[0088] 12 Curve for nitromethane, pure

[0089] 14 Curve for nitromethane with DMSO

[0090] 20 Signal

[0091] 30 temperature

[0092] 40 measurement curves

[0093] 42 Curve for nitromethane, pure

[0094] 44 curve for 5MTE, pure

[0095] 46 Curve for nitromethane with 16 wt.% 5MTE

[0096] 48 Curve for nitromethane with 24 wt.% 5MTE

Claims

Claims 1. Propellant for spacecraft and / or missiles and / or satellites, wherein the propellant comprises a fuel and exactly one additive, wherein the exactly one additive is an energetic inhibitor that acts as a phlegmatizing agent and lowers the ignition temperature of the propellant.

2. Fuel according to claim 1, wherein the fuel contains or is formed from exactly one additive 5-methyl-1-hydroxyltetrazol.

3. Fuel according to claim 1, wherein the fuel contains or is formed from exactly one additive dimethyl sulfoxide.

4. Fuel according to claim 1, wherein the fuel contains or is formed from exactly one additive ethyl ammonium nitrate.

5. Fuel according to claim 2, wherein the amount of 5-methyl-1-hydroxyltetrazol is between 10% by weight and 40% by weight.

6. Fuel according to claim 3, wherein the amount of dimethyl sulfoxide is between 8% by weight and 35% by weight.

7. Fuel according to claim 4, wherein the amount of ethyl ammonium nitrate is between 5% by weight and 20% by weight.

8. Fuel according to any of the preceding claims, wherein the exactly one additive has at least one alkyl group as an alkyl residue, in particular Ri = Ci-C6 alkyl residue, Ri = H, Ci-C6 alkyl residue, Ri, R2 = H, Ci-Ce alkyl residue.

9. Fuel according to any of the preceding claims, wherein the exactly one additive comprises a mixture of substances each having an alkyl group.

10. Fuel according to any of the preceding claims, wherein the fuel comprises or is formed from nitromethane or a mixture of nitromethane and nitroethane.

11. Fuel according to any of the preceding claims, wherein the fuel is a gel-like fuel.

12. Fuel according to one of the preceding claims, wherein a gelling agent, in particular a gelling agent, is provided in the fuel.

13. Fuel according to claim 12, wherein the proportion of the gelling agent, in particular gelling agent, is between 1 and 10 percent by weight.

14. Fuel according to claim 12 or 13, wherein the gelling agent is an organic gelling agent and is or comprises at least one of a pyrogenic silica, a low molecular weight organic gelling agent, carbon particles, or carbon nanotubes.

15. Use of a propellant according to any one of claims 1 to 14 for missiles and / or for satellites and / or for upper stages of rocket engines.

16. A method for producing a propellant according to any one of claims 1 to 14 for missiles and / or satellites and / or upper stages of rocket engines, wherein in a first process step a fuel is provided and in a second process step exactly one additive, which is an energetic inhibitor, is added, wherein the energetic inhibitor is The phlegmatizing agent takes effect and lowers the ignition temperature of the fuel.

17. The method of claim 16, wherein a gelling agent is added to the fuel, resulting in a gel-like fuel.

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